Nylvi’s Heart

The myth of Nylvi's Heart, also known as the Heart of the Anuzim, originated during the earliest days of Anuzim's construction, relating to the unusual origins of the city in lands that were previously uninhabitable for hundreds of years.

Summary

Stumbling into the volcanic caldera, the founders of the city state of Anuzim were outcasts who fled into the desert. Among them was a sorcerer, Nylvi, who led the people to a submerged caldera. The caldera, previously called Anuzim, sat on the tip of a peninsula, with a mouth to the ocean forming a natural harbour. The water was tainted, and the caldera reeked of sulfur and the black sand only amplified the heat beating upon the desert.
On the third night taking refuge in the natural harbour, the refugees started dying of starvation, with the water for the survivors running dangerously low. On the fourth night, the young sorcerer Nylvi jumped into the putrid water and disappeared into the depths. When he never returned, the survivors assumed him dead. The next morning, however, the remaining survivors awoke to the rotten air being cleared and the previously brackish water that had taunted the survivors replaced with pools of deep sapphire. Desperate, many survivors drank the water, finding their thirst quenched.
After drinking their share, the survivors noticed a faint red glow piercing the blue water from below. It pulsed like a heartbeat and grew in intensity before dimming again three days later. On the fourth night, the remains of a damaged and abandoned ship washed up on shore with supplies. The survivors turned the remnants of the ship into the first structures on the city-state of Anuzim, including what eventually became known as the Alderman’s Tankard. Within hours, they found that fish were now populating the caldera.
From this point onwards, the red light grew and faded with intensity. Many believe that since Nylvi sacrificed himself to the water that night, the glow is what remains of his heart, and any time it glows brightly, Nylvi’s Heart is hearing the struggles of the dejected and struggling.

Historical Basis

Although indeed a group of travellers fled Najadu and into the desert, eventually founding Anuzim next to the previously uninhabitable shores, stories of Nylvi and his feats have become so widespread with little historical evidence to support them that it's difficult to tell fact from fiction. Since Nylvi is credited as one of the founders of Anuzim, it hardly seems credible that he would have disappeared before the city's official construction.
What we do know is true, however, is that the red glow beneath the caldera persists to this day. There have been attempts to identify the glow but nobody who has tried has managed to make it to the bottom of the caldera to the source of the glow.